Abstract: To prevent the injury to erector muscle caused by repetitive ipsilateral lifting,by using the technology of sEMG,factors influencing left-right erector spinae muscle fatigue were evaluated in this paper.Acting on the experiment requirements,twelve male volunteers completed the repetitive form,right-side lifting work of eight task groups with the workpieces of different weights,frequencies and angles.The relevant sEMG signals were recorded.Then a multiple stepwise regression analysis was made to get the load factosr of erector spinal muscle fatigue.It turned out that with the increase of load factors,the mean power frequency(MPF) is reduced,the average electromyography(AEMG) is increased,and the MVE% is increased,that the maximal values of the erector spinae around the maximal load are (64.85%±11.89%) MVE and (41.24%± 9.77%) MVE respectively,that left and right erector spinae muscles are both obviously fatigued when completing the repetitive lifting work of each task group and there is a difference between them in the degree of fatigue,and that the factors affecting the repetitive ipsilateral move come in the order of weight,angle and frequency.

Key words: surface electromyography(sEMG), relocation load, erector spinae muscle, maximum voluntary contraction electromyography (MVE%), fatigue